Miconia chemillensis L. A. Cárdenas, 2014

Cárdenas, Lizeth A., Burke, Janelle M. & Michelangeli, Fabián A., 2014, Five new species of Miconia (Melastomataceae) from the Central Peruvian Andes, Phytotaxa 188 (3), pp. 121-134 : 124-126

Miconia chemillensis L. A. Cárdenas sp. nov. ( Fig. 2 )

Shrub or treelet, young stems terete, glabrous, on the blade surface mostly glabrous but with minute glandular trichomes, glomerulate panicle, flowers sessile, 5-merous, stamens dimorphic, antesepalous stamen filaments with an inflection towards the apex and connective with two minute ventral appendages, antepetalous lacking basal connective appendages.

Type:— PERU. Pasco: Oxapampa, Huancabamba , sector San Daniel , 10˚26’37’’ S , 75˚ 26’57” W, 2171 m, 9 September 2006 (fl) , L. Cárdenas , G. Castillo & J. Mateo 823 (holotype HOXA!, isotypes AMAZ, CUZ!, HUT, MOL!, MO!, NY!, USM!) .

Shrub or treelet, 4–7(–10) m tall. Stems terete to slightly flattened when young, glabrous, internodes longitudinal ridges absent, nodal line raised and slightly brighter than the stem. Leaves isophyllous; petiole 1.5–2.5 cm long, glabrous; blade 15–25 × 3.5–8 cm, elliptic membranaceous, base acute to broadly acute, apex narrowly acute, often narrowing below the attachment of the first pair of secondary veins, margin entire to loosely sinuate; secondary veins 1 pair plus 1 pair of faint marginals, shortly plinerved [diverging ca. 0.7 cm above the base, symmetrical or slightly asymmetrical (even on the same branch)] to basally nerved, tertiary veins percurrent, evenly spaced every 4.5–5.5 mm, the quaternaries reticulate, areoles 1.5–2 mm wide, veins flat on the adaxial surface, the primary and secondaries raised, tertiaries and quaternaries flat on the abaxial surface; adaxial surface and primary and secondary veins glabrous; abaxial surface pale green, the surface mostly glabrous but with minute very sparse glandular trichomes, the primary and secondary veins with sparse glandular sessile trichomes, <0.05 mm. Inflorescences terminal, glomerulate panicle, 12–15 cm long; peduncles slightly quadrangular and widening at the nodes, pale yellow, towards the base with a dense covering of stellate trichomes; bracts and bracteoles early caducous. Flowers sessile. Hypanthia 2 mm long, shortly broadly tubular to funnelform, 1.8–2 mm wide at the torus, with an external indumentum of dense stellate trichomes ca. 0.05 mm, internal surface smooth, glabrous. Calyx open in bud, tube ca. 0.4 mm long at anthesis, lobes ca.0.5 × 0.8 mm, broadly deltoid, with sparse stellate trichomes, pale green yellowish; calyx teeth reduced and blunt, pale green. Petals 5, 1.5–2 × 1.4–1.6 mm, broadly obovate, spreading, bright white at anthesis (drying pale brown), glabrous, the apex emarginate, the base cuneate, the margin minutely ciliate. Stamens diplostemonous, dimorphic, around the style at anthesis; antesepalous stamen filaments ca. 1.5 mm long with an inflection 0.3–0.4 mm from the apex, glabrous, white; anthers with 2 locules, 1.6–1.9 × ca 0.5 mm, oblong, the thecae occupying only the upper half, opening by 1 broad apical pore, the connective extending ca. 0.7–0.85 mm below the thecae, linear, with two spheroid ventral appendages, pale yellow, glabrous; antepetalous stamen filaments 0.9–1.2 mm long with an inflection very near the apex (<0.15 mm), anthers ca. 1.25–1.45 mm long, lacking basal connective appendages, the thecae occupying the upper half, opening by 1 broad apical pore. Ovary 3-locular, 1/2 to 2/3 inferior, the free portion projecting up to 0.5 mm, cylindrical, glabrous, the apex with a 5-lobed collar ca. 0.2 mm long; style 2.7–3 mm long, straight, white, glabrous; stigma truncate, ca. 0.4 mm wide. Mature berries not seen.

Habitat and Distribution:— Endemic to the central forests of Peru in Huancabamba , Oxapampa. Miconia chemillensis is known only from the type and has been collected in the border the Yanachaga Chemillén National Park, in the San Daniel area (2171 m) .

Etymology:—This new species is named after the Yanachaga Chemillén National Park where is found. Chemillén is a Yanesha word that means “burnt” and it refers to the aspect of the mountains of the region.

Conservation Status:— Miconia chemillensis is only known only from one population a at the border of the Yanachaga Chemillen National Park, in an area that is highly degraded and under logging pressure. Based on the paucity of collections it should be considered Data Deficient (DD), following the IUCN criteria (2001) as implemented by the IUCN guidelines (2011). However, based on its limited distribution and endangered habitat, we recommend that this species is considered Critically Endangered.

Discussion:—The anthers of Miconia chemillensis have a slender but prolonged connective with apically widening thecae that open by broad pores. These characteristics place this new species in the traditional definition of Miconia section Hypoxanthus (Richard ex de Candolle 1828: 180) Triana ex Hook. f., in Bentham & Hooker (1867: 764), also known as M. section Glossocentrum (Crueger 1847: 111) Triana ex Hook. f. in Bentham & Hook (1867: 763); see Goldenberg (2000). The great majority of the species in this group are from Eastern Brazil but eleven species are known from Peru. The members of Miconia section Hypoxanthus in Peru are mostly found below 800 m elevation in Amazonian forests, while M. chemillensis was collected in cloud forests ca. 2500 m elevation. Molecular phylogenetic work is necessary to ascertain whether this species is indeed closely related to the Brazilian species of Miconia section Hypoxanthus .

The flowers of M. chemillensis closely resemble those of M. semisterilis Gleason (1936: 535) , especially in calyx, style and anther shape. However, M. chemillensis has dimorphic anthers (as opposed to isomorphic in M. semisterilis ), and 5-merous flowers (vs. 4-merous). Additionally, the inflorescence of M. chemillensis is glomerulate (flowers not clustered in M. semisterilis ) and the leaves are glabrous abaxially (vs. densely stellate-pubescent). Vegetatively M. chemillensis resembles M. klugii Gleason (1931: 240) , also from Peru, but differs in leaf pubescence (glabrous vs. densely stellate) and the anthers of M. klugii lack the connective below the fertile portion of the thecae.

Figures

FIGURE 2. Miconia chemillensis. A. Flowering branch. B. Inflorescence detail.C. Flower at anthesis. D. Antepetalous stamen, side view. E. Antesepalous stamen in side (L) and ventral view (R) (Cardenas 823, NY).